[Wolff-Parkinson-White syndrome with paroxysmal supraventricular tachycardias of the fetus and the newborn--case report]

Paroxysmal supraventricular tachycardia causing an intrauterine congestive heart failure was diagnosed in a fetus at 33 week's gestation. After maternal digitalization the tachycardias and the signs of heart failure disappears. Postpartum a Wolff-Parkinson-White syndrome was recognised by electrocardiography. The paroxysmal supraventricular tachycardias of the newborn was terminated abruptly by intravenous application of propafenon. Recurrences were prevented by the oral administration of propafenon.

[The effect of anti-arrhythmic drugs on myocardial function (author's transl)]

In a randomized study the influence of anti-arrhythmic drugs on left ventricular myocardial function was tested. Propafenon, mexiletine, tocainide, disopyramide or placebo were given over seven days on top of basic treatment with digitalis, diuretics and nitrates. Propafenon, mexiletine, tocainide and disopyramide had negative inotropic effects of 16, 17, 19 to maximally 30%, respectively. Echocardiography was especially suitable for serial assessment of left ventricular failure. Propafenon, mexiletine and tocainide are the anti-arrhythmic drugs of choice in the treatment of cardiac arrhythmias. However, the at times marked decrease in contractility must be taken into account when the decision is made whether a given arrhythmia requires treatment or not.

[Profound granulocytopenia in a patient treated with propafenon ]

A case report concerning a 75 year old female patient whose treatment of multifocal ventricular extrasystoles and a ventricular tachycardia after an acute myocardial infarction consisted of multiple drugs, one of them being the antiarrhythmic substance Propafenon, is given. The patient developed a profound, but reversible, granulocytopenia, which disappeared nine days after discontinuing of most of the drugs. With the exemption of Propafenon all of the drugs were reinstituted after the remission: The not anymore needed ones only for a few days, all others until now, without ill effect. The patient is doing fairly well one year after this episode.

[Antiarrhythmic efficacy of mexiletine, propafenone and flecainide in ventricular premature beats. A comparative study in patients after myocardial infarction (author's transl)]

In 12 patients with coronary artery disease, 11 of them with previous myocardial infarction, the antiarrhythmic effects of orally administered flecainide (F.), mexiletine (M.) and propafenone (P.) were examined. The doses amounted to 400 mg F., 600 mg M., and 900 mg P. daily. The administration was made randomized with a change between placebo and verum periods with a duration of 3 respectively 4 days. The 3 antiarrhythmic agents reduced significantly the number of ventricular premature beats (VPB), the reduction of VPB amounted to 94.2% (F.), 80.2% (P.), and 52.8% M.). Repetitive VPB were reduced about 98.8 % (F.), 96.8% (P.) and 83.33% (M.). The Lown-Index diminished by about 1.45 classes (F.) 1.18 classes (P.) respectively 0.55 classes (M.). A complete suppression of VPB was obtained only in one patient under medication with F. F. and P. lengthened the duration of P, PQ and QRS, whereas M. did not affect these parameters. Heart rate and QT remained unchanged. Subjective side-effects of the 3 agents were similar. Without of the influence on the ECG, objective side effects were missed. The long plasma half-life of F. (19.0 +/- 5.2 h) guarantees an antiarrhythmic effect over a period of 24 hours if the substance is administered twice daily. The large variance of plasma half-life can cause some difficulties in the finding of individually required dose of F.

[Propafenon and propranolol in the management of cardiac extrasystoles (author's transl)]

The anti-arrhythmic effectiveness of propafenon (3 x 150 mg daily) combined with propranolol (3 x 20 mg daily) was compared with that of each drug alone in 15 patients with stable ventricular and (or) supraventricular extrasystoles. The frequency of extrasystoles decreased on propafenon alone by 70% (P less than 0.05), without further decrease on additional propranolol administration. Propranolol alone on average caused no significant decrease infrequency (35%). The most important ECG changes with the combined treatment consisted of a definite increase in P-Q interval by an average of 25% (P less than 0.01) while with propafenon alone it was 13%, with propranolol alone 19% . Propafenon plus propranolol decreased heart rate by a mean of 17% (P less than 0.01). The additive effect of both substances can lead to an inhibition of atrioventricular conduction and of sinus node function.

Comparison of the efficacy of propafenone versus disopyramide for complex premature ventricular contractions. Evaluation with long-term monitoring

Interpreting the results of this study, propafenone (Rytmonorm), administered orally in a dose of 900 mg daily, was more effective than disopyramide in a dose of 600 mg daily, in the treatment of patients with complex premature ventricular contractions (PVCs). The study was performed in 12 patients, with several Holter ECG monitorings to obtain quantitative data of the effectiveness in the same patient of the new drug propafenone in comparison with disopyramide in a documented effective oral regimen. A quantitative analysis of PVCs was obtained with a computer assisted detection. Clinical effectiveness, considered as 70--80% reduction of total number of PVCs, was obtained in 8/12 patients for propafenone and 6/12 for disopyramide, or as 50% reduction with suppression of all complex PVCs (couplets, repetitive, multiform and bigeminy) was obtained in 11/12 for propafenone and 9/12 for disopyramide.

[Determination of propafenone in plasma by HPLC with direct isotope dilution (author's transl)]

A high performance liquid chromatography method based on the principle of direct isotope dilution is described for the determination of propafenone in plasma. With a sample volume of 2 ml and quantification by peak height measurements the lower limit of detection is about 2.5 micrograms/l, and the lower limit of determination about 10 micrograms/l. Values up to 250 micrograms/l are subject to a mean weighted relative error of 3.5%. At concentrations above 20 micrograms/l this method shows the same accuracy and reproducibility as the analytical procedure employing internal standardization with analogues. The method is made independent of possible storage losses by internal standardization of each sample immediately after withdrawal.

Electrophysiological and antiarrhythmic properties of propafenon in isolated cardiac preparations

Propafenon, a new antiarrhythmic drug, caused a 30% decrease in maximal driving frequency and a 65 ms net increase in functional refractory period of isolated guinea pig atria at a concentration as low as 0.5 microgram/ml. The spontaneous rate of isolated atria and the contractility of electrically driven ventricular strips were reduced after treatment with propafenon 1 microgram/ml. Propafenon 0.5 microgram/ml also altered action potentials of sheep Purkinje fiber. It reduced the action potential and overshoot amplitudes, decreased the maximum rate of depolarization of the action potential upstroke in a frequency-dependent fashion, shortened the action potential and effective refractory period, and depressed the membrane responsiveness. Moreover, propafenon antagonized the chronotropic and inotropic effects of isoprenaline in isolated guinea pig heart preparations; the pA2 value was about 6.4. Finally, propafenon possessed very weak calcium antagonist properties, being about 100 times less potent than verapamil in this respect. We conclude that propafenon is an antiarrhythmic drug with beta-adrenoceptor blocking and "membrane stabilizing" activities in the same range of concentrations and that it has a calcium antagonistic activity only at much higher concentrations.

The influence of some cardiodepressant drugs on the histamine-induced restoration of contractility in potassium-depolarized heart preparations

The ability of some drugs to affect calcium movements in cardiac fibers was tested using a simple method. Guinea-pig ventricular strips were depolarized by 22 mM K+ and their mechanical activity was restored by histamine (10(-5) M); in in these conditions, the effects on contractility of the classic calcium antagonistic drugs nifedipine, verapamil and D600, of the antiarrhythmic drugs lidocaine, quinidine and propafenon, and of a barbiturate, thiopental, were assessed. These drugs were chosen because all of them have been reported as affecting cardiac contractility. It was observed that the ED50 values obtained for the calcium antagonists were in good agreement with those calculated by other authors using different techniques. Moreover, it was found that at high concentrations either the antiarrhythmic drugs or thiopental showed a cardiodepressant activity; the likely explanation of their effects is discussed.

[Propafenon-induced cholestatic liver injury--a further example for allergic drug hepatitis (author's transl)]

In the course of cholestatic liver injury after propafenonhydrochloride medication, a high increase of the glutamatedehydrogenase up to the twenty fold of the normal range was followed by a marked raise of SGOT and SGPT. Cholestatic enzymes like gamma-glutamyl transpeptidase and alkaline phosphatase reached their maxima a week later. Within two weeks the hepatic cell enzymes and within four weeks the cholestatic enzymes have returned spontaneously to normal.

[Clinical study of a new anti-arrhythmic drug: propafenon. Short and long-term results]

Fifty patients with atrio-ventricular arrhythmias were treated with the new antiarrhythmic drug propaferon. A dose of 70 mg (1-1.5 mg/kg), was injected slowly into a vein (2-3 min), in 16 cases. In the other 34 cases a dose of 450-900 mg/24 hours was given orally. Propafenon is a drug which acts on the permeability of the membrane and also as a local anaesthetic. Its efficiency has been demonstrated in the treatment of arrhythmias. In our series, ventricular arrhythmias were suppressed in 76.8% of the cases (33 patients), while the ventricular extrasystoles were reduced in 18.6% of the cases (8 patients). There was no action in 4.6% of the cases (2 patients). The drug was not useful in the treatment of atrial arrhythmias. Unwanted side-effects (arterial hypotension, conduction disorders, etc.), were not seen when intravenous doses of less than 2 mg/kg, were administered. However, electrocardiographic changes (widening of the QRS, prolongation of the PQ interval, etc.), were observed in those patients who received doses greater than 450 mg/24 hours. In these patients, there was a close correlation between the dose administered and the prolongation between the dose administered and the prolongation of the conduction times. We believe that the amount of myocardial degradation and the age of the patient are directly related to the appearance of conduction disorders. This relation is greater when a larger dose is administered. The advantages that this new drug has over other antiarrhythmics are the methods of administration (oral and intravenous). Both these methods may be used simultaneously to maintain a stable sinus rhythm or the rapid intravenous method may be followed by the oral maintenance one.

[Propafenon therapy of arrhythmias in infancy and childhood (author's transl)]

The therapeutic dose range of propafenon was studied in 28 infants and children aged 5 days to 15.2 years (mean 8.8 years) with the following cardiac arrhythmias: paroxysmal tachycardia (20) atrial flutter (5) ventricular extrasystoles (2) and junctional tachycardia (1). With the intravenous administration of the drug in a dosage of 1.03-3.2 mg/kg/d (mean 2.28 mg/kg/d) in patients less than 15 kg and of 0.71-2.06 mg/kg/d (mean 1.26 mg/kg/d) in patients more than 15 kg body weight arrhythmias abolished. In the same patients the oral dosage was 12.2-22.6 mg/kg/d (mean 16.03 mg/kg/d) and 7.2-16.6 (mean 11.12 mg/kg/d). After 10 to 14 days a therapeutic serum level above 150 ng/ml could be maintained by a reduced oral dosage of 5.7-13.3 mg/kg/d) mean 8.5 mg/kg/d) and 3.6-11.1 mg/kg/d (mean 6.33 mg/kg/d) respectively. There were no side effects except for transitory by elevated gamma-GT in 8 patients. During a follow-up period of 1 month to 2.2 years (mean 1.6 years) 20 patients had no more arrhythmias, in 7 the number of arrhythmic attacks was reduced, and in 1 therapy failed.

[Beware: propafenon potentiates the effect of oral anticoagulants]

In a 68 years old female patient with premature ventricular contractions who was treated with phenprocoumon (Marcumar) because of pulmonary infarction, propafenon (Rytmonorm)--a new anti-arrhythmic drug--lead to an increased effect of coumarin. Inspite of pausing with coumarin for eight days the low Quick rates (less than 15%) did not increase until propafenon was stopped. Afterwards the coumarin treatment was continued with 1,5 to 3 mg a day. In case of a combined treatment with propafenon and coumarin Quick rates should be controlled frequently.

[Electrophysiological classification of newer antiarrhythmic drugs (author's transl)]

Newer antiarrhythmic drugs are tentatively classified on the basis of their influence on the transmembrane action potential, the fast sodium inward current and its kinetics, and the slow inward current which is primarily carried by calcium ions. Disopyramide is probably a quinidine-like antiarrhythmic drug, while the effects of aprindine, lorcainide, and tocainide resemble those of lidocaine. Mexiletine and propafenon cannot be classified definitely on the basis of the hitherto available electrophysiological data. Besides their effects on the fast inward current these substances may have additional calcium antagonistic properties.

Effects of propafenone on TEA-induced action potentials in vascular smooth muscle of canine coronary arteries

The Ca++-dependent, TEA-induced action potential is blocked by propafenone in a dose-dependent manner. Such results suggests that in coronary arterial smooth muscle one mechanism of action of propafenone is to inhibit Ca++ inward current.

[Combined use of propafenon and lidoflazine in chronic atrial fibrillation and flutter (author's transl)]

Forty-seven patients with chronic atrial fibrillation and (or) flutter in whom the clinical picture and the length of arrhythmia indicated that drug-mediated cardioversion should be tried were treated with a combination of lidoflazine and propafenon. The average daily dosage was 600 mg for propafenon and 180 mg for lidoflazine. Duration of treatment was limited to 8 days. Return to sinus rhythm was achieved in 34 patients. In comparison with monotherapy combined use of the drugs thus led to a clear-cut increase of the conversion rate. Dosage reduction of these differently acting substances decreases the risk of toxic side effects, particularly as both substances have different side effects which in part cancel each other out. It can be assumed that ventricular extrasystoles seen during treatment with lidoflazine as precursor of malignant tachycardia can be suppressed or eliminated by propafenon.

[Disturbances of potency and spermiogenesis due to propafenon (author's transl)]

Loss of potency and spermiogenesis in a 43-year-old man could be demonstrated as due to propafenon by reexposition.

[Serum concentration and AV-conduction time in oral treatment with propafenone during a several-days period (author's transl)]

In 6 patients with stable cardiac dysrhythmias (ectopic beats) an oral dose of 300 mg propafenone was given in eight-hour intervals for 4-6 days. A significant correlation between serum concentration and prolongation of PQ-time interval was found. Therefore the changes of PQ-time interval can be used for the control of dose of propafenone.